Two motion selective switches



5, 1957 H. VSENGEBUSCH 2,780,675

TWO MOTION SELECTIVE SWITCHES Filed Nov. 27, 1951 2 Sheets-Sheet 1 'S JS O 3 w 0 n :2

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ATTY.

Feb. 5, 1957 SENGEBUSCH 2,780,675

TWO MOTION SELECTIVE SWITCHES Filed NOV. 27, 1951 2 Sheets-Sheet 2 V v JNVENTOR. HANS SENGEBUSCH ATTY.

United States Patent TWO MOTIQN SELECTIVE SWITCHES Hans Sengebusch, Chicago, Ill., assignor t0 Automatic Electric Laboratories, Inc., Chicago, Ill., a corporation of Delaware Application November 27, 1951, Serial No. 258,404

9 Claims. (Cl. 179-2752) The present invention relates to improvements in two motion selective switches, and more specifically to an improved escapement flat type switch operating in two directions for use in telephone systems.

An object of this invention is to provide for the rapid and'positive operation of a two motion escapement fiat type switch.

Another object of this invention is the operation of the switch by only two electromagnets, thereby keeping the number of parts of the switch to a minimum.

One feature of this invention is the use of a novel three level gear-in combination with the other necessary parts oi the switch.

Other objects and features will. become apparent from the perusal of the following specification and drawings of which: Fig. 1. is a top plan view of one embodiment of the invention, Fig. 2 is a sectional perspective view of the three level gear, more clearly showing its combination with the other elements of the switch, and Fig. 3, is a sectional perspective view of the mechanism for controlling the two motion stepping of the switch.

The present embodiment is the preferred embodiment, but it is to be understood that changes can be made in the present embodiment by one skilled in the art without departing from the spirit and scope of this invention.

The switch disclosed is of the escapement drive type in which power for operation is derived from a spring 3:) in which energy is stored by the restoration of the switch from a previously advanced position. The wipers are mounted on a. rotatable carriage 66 which is first caused to rotate by a driving element 70 which is caused to rotate by means of an-escapement 49 in response to impulses to bring the wipers into position before a group of contacts, and the carriage is then locked while the wipers are moved radially relative to the carriage by the same driving element 71 and its escapement 40 into contact with set of contacts in the selected group.

To describe the general operation of the switch, reference is made to Fig. 1 wherein is shown the magnet 16 which is initially energized. This locks the carriage 66 and the driving element 76 together for rotational movement. The magnet 29 is then energized and deenergized a predetermined number of times. This frees the gear 40 for rotational movement in steps which in turn frees driving element 7% for rotational movement in steps, and the power in the tensioned drive spring 80 causes the rotation of the driving element 70 to a position before one group of the groups of bank contacts. Magnet 10 is then deenergized thereby causing the carriage 66 to be locked from further rotational movement. Magnet 2! is again energized and deenergized a predetermined number of times releasing gear 40 for rotational movement in steps, which in turn allows driving element 70 to rotate in steps, and the power in the tensioned drive spring 80 again causes the rotation of the driving element 70, which in turn causes the rotation of the gear 72, which in turn causes the wiper assembly 68 tobe moved into the selected group of bank contacts a predetermined number of steps.

Generally, the switch is restored by initially energizing the magnet 10, and then energizing and deenergizing magnet 20. As magnet 29 is operated the wiper rack 68 will be returned to normal against the bias of the drive spring by the operation of the pawl 24 mounted on the armalure of magnet The operation of the pawl 24 causes a reverse rotation in steps of the gear 40, in turn reversing the rotation of the driving element 70, in turn reversing the rotation of the gear 72, in turn restoring the wiper rack 68. When the wiper rack has been returned to normal the carriage 66 is freed from the operated rotary position and thereafter rotates together with the driving element 7%]. Further operation of magnet 20 will cause the carriage 66 and the driving element 70 to be restored to normal by means of the pawl 24 operating upon gear 40 and causing it to rotate in steps in a reverse direction as mentioned hereinbefore. The return to normal of the wiper rack 68, the carriage 66 and the driving element 70 results in the restoration of full tension in the drive spring 80. Magnet 10 is then deenergized to complete the restoration of the switch.

The present embodiment will now be described in detail with reference to Figs. 1-3. A base is provided upon which the various components of the switch are mounted. This base 5 3 may be mounted in a vertical row with any number of similar switches. The switch has a plurality of bare wire contact bani: assemblies 91 accessibie to it. These assemblies 1 are mounted in a frame 92. The frame 92 and the assemblies 91 will not be described in detail as they are shown and described in detail in my application for fiat type switches, filed July 12, 1951, Serial No. 236,377, new issued July 20, 1954 as Patent 2,634,408.

A carriage 66 and a driving element 7i) are rotatively mounted, one above the other, on the base by means of any mounting means well known in the art. As can be seen in Fig. 1 the carriage 66 is irregular in shape to facilitate the mounting of the wiper assembly 63, the lock bar 73 and the indicator means 77 thereon. As can be seen in Fig. l the driving element 79 is circulir in shape, and has a series of gear teeth 71 disposed around a section of the periphery thereof. A number of elements cause the necessary cooperation between element in and the carriage 66. Among hese are the loci; bar 73, the slot 76 in the driving element 7 the gear 72, and the drive spring 84 The drive spring is tcnsioned at all times and is fastened at one end to the element The element 86 is pivotally mounted to the base by means of. mounting means 87, and can be held rigidly in one position by the screw 33. F e 86 the permits adjustment of the tension of spring "rh': biases the element 70 in a counterclockwise sin tween the driving element 7% and he cantioned hereinbefere are the lock bar 73 and the driving eiemei '78. The loci; bar 73 is mounted at one end on the cart age 66 by means of mounting means 75. These latter mounting means are such that the lock bar 73 may be raised and lowered about these mounting means. A spring 7 is also mounted at one end by mounting means 75. The other end of the spring 74 bears against the lock bar 73 and biases it in a downward counterclockwise direction as seen in Fig. 1.

direction. The lock bar 73 has a number of projections on the other end thereof as can easily be seen in Fig. 3. Two of the projections 73b extend in a downward direc tion. The remaining projection 73a extends in an upward direction. The slot 76 in the driving element 76 is so shaped that in one relative position of the carriage 56 and the driving element 70, the projections 73b extend into the slot 76. Therefore at any time when the carriage 66 and the driving element 70 have this relative position, and the lock bar 73 is in its lowest posit on the driving element 70 and the carriage 66 will be together for rotational movement. However if the carriage 66 and the driving element 7 6 have a different relative position the projections 73b will be riding upon the upper surface of the driving element 79. The above described elements are involved in the selective rotation of the carriage 66 and the driving element 7% in a counterclockwise direction as seen in Fig. l and the selective radial movement of the wiper assemblies.

Turning next to the means for maintaining the carriage 66 stationary in any rotary position and for locking and unlocking the carriage 66 and the driving element 70, an arcuate shaped plate 15 having a series of notches along one edge thereof is shown mounted on the base 90 some distance therefrom in Figs. 1 and 3. if the lock bar 73 is raised when the carriage is in any rotary position the projection 73a on the lock bar 73 will engage one of the notches in the plate 15, the particular notch engaged depending upon the rotary position of the carriage 66. If the lock bar 73 is raised to this position the projections 73b will no longer extend into the slot 76. There fore the carriage 66 will be locked from further rotational movement while the driving element 70 will be freed from the carriage 66 and may be further rotated in a The means for raising the lock bar 73 comprises the element 11 and the springs 14. Two mounting elements 12 are mounted on the base 90. The element 11 as seen in Figs. 1 and 3 comprises the armature of magnet and is pivotally mounted between the mounting elements 12 by means of mounting means 13. The other end of element 11 has an arcuate shaped portion ila thereon. This portion 11a is disposed beneath the tip of the lock bar 73 and the plate 15. The springs 14 are rigidly attached to one end of the element 11. The other ends of the springs 14 bear against the plate 15 and bias the portion lla in an upward direction as seen in Fig. 3. The bias of the springs 14 is greater than bias of the spring 74 so that tip 73a of the lock bar 73 will be forced into engagement with one of the notches in the plate 15 when the carriage is disposed in one of its rotary steps. Therefore when the element 11 is pivoted downward by magnet 19 the tip 73a is freed from the plate 15, and the projections 73b extend into the slot 76 locking the carriage 66 and the driving element 70 together, and when the element 11 is released by deenergizing magnet 10, the bias of the springs 14 will raise element 11a to lock the carriage 66 to the plate 15, while not interfering with any further rotational movement of the driving element 7%. When the driving element 7 0 is rotated after the carriage 66 is locked to bring the carriage 66 into a relative position other than the above mentioned one, the projections 73b will be riding upon the upper surface of the driving element 76 and the projection 73a will be engaged with one of the notches in the plate 15. Now if magnet 10 is energized and the element 11 is pivoted downward and the driving element is rotated in a clockwise direction as seen in Fig. 1, the bias of the spring 74 will force the projections 73b into the slot 76, and free the projection 73a from the plate 15, when the driving element 79 and the carriage 66 attain the above-mentioned relative position.

The means for controlling the movement of the element 11 comprises an electromagnet 16 mounted on base 90. The mounting elements 12 are attached to the core of the magnet 10 and the element 11 is pivotally mounted to the mounting elements 12 and extends over the core ofthe magnet 19 to form a magnetic circuit for the magnet To next describe the gear as and its function in the switch, reference is made to Figs. 1 and 2. Gear 40 is mounted for rotational movement on the base 90 by means of mounting means 471. Gear 40 is a three level gear as can easily be seen in Fig. 2. The teeth 43 project upward and are disposed around the periphery of the gear 40 to form the first level. Ratchet teeth 42 form the second level, and gear teeth 44 form the third level. All of the teeth are immovable with respect to each other. The third level teeth 44 are in mesh with the gear teeth 71 on the driving element '70.

To next describe the apparatus cooperating with first and second levels of gear 46, reference is further made to Figs. 1 and 2. This apparatus may be divided into two main parts, the escapement means for operating the switch, and the restoring means for returning the switch to normal after it has been operated. The escapement means comprises the electromagnet 20, its armature 22, the pawl 24, the pawl tip 24!), the element 47, the element 45 and the first level gear teeth 43 of the gear 40. The electro magnet 20 is mounted on the base 90 in any well known manner, and comprises a heel piece 21 and an armature 22 pivotally mounted thereon by means of mounting means 23. For positioning the armature 22 an element is provided. The element 35 is mounted to the base 90 by means of mounting screws 37. A bias spring 2? attached to the element 35 and the armature 22 biases the armature in a clockwise direction as seen in Fig. 1. A stop 33 mounted on the element 35 acts as a back stop to limit the clockwise movement of the armature 22 as seen in Fig. 1. To the other end of the armature 22, a pawl 24 is pivotally mounted by means of mounting means 31. The pawl 24 has two projections, 24a and 24b, on the end thereof. A spring 32 attached to the armature 22 and the pawl 24 biases the pawl 24 in a counter-clockwise direction as viewed in Fig. l. The element 47 has an irregular shape as can be seen in Figs. 1 and 2. The element 47 is pivotally mounted on the base 50 by means of mounting means 46. An element 59 is mounted on the base Q0. A spring 48 is attached to this element 59 and the element 47, to bias the element 47 in a clockwise direction as viewed in Figs. 1 and 2. A stop 5% on the element 59 limits the clockwise rotation of element 47. The element 47 has a projection 47b, the tip of which is disposed opposite the projection 24b of the pawl 24. Another projection 47a of the element 47 is so disposed as to engage the teeth 43 of the first level of the gear 46. A stop 59a on the element 59 limits the counterclockwise rotation of element 47. The element is also pivotally mounted to the base by means of mounting means 46. This element is biased in a counterclockwise direction as viewed in Fig. l by means of the spring 49 attached to the element 47 and the element 45. The element 45 is so disposed as to be engageable with the teeth 43 of the first level of the gear 40. A small projection on the element 47 is engageable with the element 45. The element 45 and the tip 47a of the element 47 act as detents for the escapement function of the switch. The restoring means comprises the electromagnet 20, the armature 22, the pawl 24, the pawl tip 24a, the detent 25, and the ratchet teeth 42 on the second level of the gear 40. The projection 24a of the pawl 24 is so disposed as to be engageable with the ratchet teeth 42 of the second level of the gear 40. The detent 25 is pivotally mounted to the base by means of mounting means 26, and is biased in a counterclockwise direction as viewed in Fig. 1 by the spring 27, one end of which is attached to the detent 25, the other end of which is attached to the base 90 by means of the adjustable element 28. The detent 25 is positioned adjacent to the projection 24a of the pawl 24 so as to be engageable with the ratchet teeth 42 of the second level of the gear 40.

In order that the stepping function and restoration function of the switch may be accomplished without increasing the number of electromagnets in the switch a control bar 60 and associated parts is provided therefore. As seen in Fig. l the control bar 60 has an irregular shape, and is moveably mounted on the base 90 through the slot 62 in the control bar 60 by means of mounting means 61. The control bar 60 can be rotated in either direction about the mounting means 61, and can also be radially moved the length of the slot 62. The lock bar 60 is biased radially away from magnet 20 by means of spring 60d which is attached to post 52 mounted on the control bar 60 and mounting means 61. The control bar 60 has a notch 600 in one end thereof. A bar 82 is pivotally mounted to the base 99 by means of mounting means 84 and screws 85. A spring 83 attached to the means 84 and the bar 82. biases the bar in a clockwise direction as viewed in Fig. 1. This bar 82 is capable of engaging the notch 600 in the control bar 6% under conditions to be described below. Control bar 60 has another notch 6% on the same end thereof. This notch is engageable with one end of a lever 17. The lever 17 is pivotally mounted to the plate by means of mounting means 18. The other end of the lever 17 engages an edge of the element 11, so that as the element 11 is pivoted the lever 17 is pivoted, which in turn will move the control bar 60 toward or away from the electromagnet Zii if the lever 17 is engaged with the notch 60b. The construction of the lever 17 can easily be seen in Fig. 3. A stop 63 mounted on base 99 limits the clockwise rotation of the control bar 69 as seen in Fig. l. The post 52 on the control bar 60 serves a dual function; besides being a mount for springs 60d, it also is engageable with the bell crank 50. The bell crank 59 is pivotally mounted to the base 96 by means of mounting means 51. The other end of the bell crank is engageable with one edge of the element 47. Therefore if the control bar is moved radially toward the magnet 20, post 52 will pivot the bell crank 50, which will in turn pivot the element 47 there by moving the projection 47b of the element 47 out of possible engagement with the projection 24b of the pawl 24. Control bar 60 also has a projection 65 attached thereto. This projection extends in an upward direction intersecting the plane in which the pawl 24 and the detent 25 move. It can thus be seen that if the control bar 60 is moved in a radial direction away from magnet 20 the projection 65 will engage the detent forcing it out of engagement with the ratchet teeth 42 of the second level of the gear 40. The detent 25 in turn will move the projection 24a of the pawl 24 out of engagement with the teeth 4-2 of the second level of the gear 40. The control bar 60 also has a projection 66a extending therefrom as can be seen in Figs. 1 and 3.

This projection 66:! is engageable with post 64 mounted on the under side of the driving element 76. The post 64 makes contact with the projection 60a only when the switch is in the normal position.

To further describe the remainder of the switch, reference is made to Fig. l. A wiper assembly 68 is slidably mounted upon the carriage as. A pair of channels 69 mounted upon the carriage 66 form the track for the radial movement of the wiper assembly as. Along one edge of the wiper assembly as is a rack 67 composed of a series of gear teeth. These gear teeth 7 engage the gear v 72, so that any rotation of the gear causes a radial movement of the wiper assembly 68. Multiple wipers form a part of the wiper assembly 63. The construction of these wipers will not be described in detail as their construction is well known in the art. A pair of stops 81 mounted upon the base 95 determine the limits of rotation of the carriage 65.

There is also provided on the carriage 66 a pair of indieating arms '77 as can be seen in Fig. i. There is a series of numerals placed on the upper side of the driving element 70. An arcuate shaped indicator 78 having numerals thereon is mounted on the base by means of the mount ing means 79. Now as the carriage 66 is rotated to any rotational position the indicating arms 77 will straddle the numeral on the scale '78 indicating the extent of rotation thereof. Then as the driving segment 70 is rotated relative to the carriage 66, the numerals on the upper surface of the driving element 70 will pass between the indicating arms 77 to indicate the position to which the wiper assemblies have been moved radially.

The switch is also provided with a number of contact spring assemblies 35) and 54 as can be seen in Fig. 1. These contact spring assemblies 30 and 54 are well known in the art and a detailed description thereof is unnecessary. Contact spring assembly 54 is operated by a post 53 mounted on the control bar 60. Contact spring assembly 30 is operated by a toggle joint interrupter unit. This unit consists of a lever having three arms as can be seen in Fig. 1. One arm is engageable with the contact spring assembly 30. Another arm 33 is forked and is engageable with a post 34 mounted on the armature 22. The third arm has a spring 36 attached thereto; the other end of the spring being attached to the element 35. The toggle joint lever is pivotally mounted on the element 35 and the spring 36 biases the lever in a clockwise direction as viewed in Fig. 1. Therefore it can be seen that as the armature 22 is operated the toggle joint interrupter unit will operate the contact spring assembly 3th The contact spring assemblies 30 and 54 can be used in conjunction with a circuit to automatically energize and deenergize magnet 26 to restore the switch it it has been operated.

A detailed description of the operation of the switch can now be made, and reference is made to Figs. 1, 2 and 3. Magnet it) is first energized, and this results in the arcuate portion of element 11 being pivoted downward. The bias of spring Li then maintains the projections 73b of the lock bar 73 in the slot 76. The lever 17, also pivoting, does not engage the slot dtib of the control bar 69 because of the post 64- mounted on the under side of the driving element 76 which maintains the control bar 69 in the position shown in 1 when the switch is at normal. The carriage 66 and the driving element 70 are now locked together for rotational movement of the wipers. The magnet 29 is then energized and deenergized a predetermined number of times, the number of times corresponding to the group of bank contacts to be selected. Since the control bar 61% was not moved by the lever 17, the control bar it is maintained by its bias spring 66:! away from magnet 2 Therefore the projection. 65 of the control bar 6d maintains the detent 25 and the projec tion 240 of the pawl 24 out of possible engagement with the gear 43. However, the projection 24b of the pawl 24 is so disposed that the energization of magnet 20 and the consequent operation of its armature 22 and pawl 24 will cause projection 24!) to project against the element 4712 thereby causing element 47 to pivot in a counterclockwise direction as viewed in Fig. 1. The projection 47a of the element 47 will then be withdrawn from engagement with the teeth of the first level of gear 41 and the element &5 begins to pivot in a counterclockwise direction due to its bias spring 4h. The drive spring 8i will then rotate the carriage 66 and driving element 713, the gear 49 also rotating due to the engagement of the teeth 71 of the driving element 7%) with the teeth 44 of the third level of the gear 40. The pivoting element 45 will then engage one of the teeth 43 of the first level of the gear 40, thereby limiting the rotation of the carriage 66 to one rotary step. Upon the restoration of the armature 22 of the magnet 20, element 47 will pivot in a clockwise direction as viewed in Fig. 1 under the power of its bias spring 48. Projection 47a of the element 47 will then engage one of the teeth 43 of the first level of the gear 40 to prevent further rotation of the gear 40 as the element 45 is forced out of engagement with the teeth 43 by the projection on ass-0,675

'20 is energized and deenergized until carriage 66 .has

reached'theselectedrotary position before the selected group of bank contacts 91. Magnet 1% is then deenerg'ized. 'The notch 69b will then engage the lever 17 under the power of the bias spring :83 causing lever 32 to force the control bar 69 in a counterclockwise direction as viewed inFig. .1 as the lever 17 turns to normal. Also, the tip 73a will "be positioned beneath one of the notches in the plate and the restoration of the magnet it will cause the surface 111; of the element 11 to pivot upward. This will cause the tip 73:! of the lock bar 73 to engage the aforementioned .notch in theplate 15. The projections'73b of the lock bar '73 will be withdrawn from the slot 7,6.in the driving element 70. The carriage 66 will then belockedfrom further rotational movement, however the driving element 70 .will 'bejfree to rotate further. Thetdetent ZSan-dthe projection 24a of the pawl 24 will still not contact theteeth of the gear iittas the control bar 60' has not been moved against its bias spring di d. The magnet 26 is then energized and deenergized a selected number of times corresponding tothe selected bank con tacts of the selected group of bank contacts. The projection,24b of the pawl 24 will again operate against the element 47 and the above described rotation of the driving element 76 and the gear 40 under the power of the drive spring 80 will be repeated. The rotation of the driving element 74 in steps will cause the rotation of the gear 72 in steps. The gear 72 in turn will act upon the rack teeth 67 of the wiper assembly 68 to project the wiper assembly 68 radially in steps intothe selectedgroup of bank contacts to theselected bank contacts. The switch has now 'been'operated, and a detailed description of the restoration of the switch will be described below.

,To restore the switch the magnet 10 is energized. This causes the element 11 to be pivoted downward. The lever vll'which now engages the notch dab of the controlbar 60 will move the control bar 60 against the bias of its spring 60d toward magnet 20, and the lever 82 will engage the notch 600 of the control bar 69 under power of the spring 83. Also, the surface 11a of the element 11 will no longer hold the tip 73a of the lock bar 73 in one of the notches of the plate 15, and spring 74 will force the projections 73b of the lock bar 73 against the upper surface of the driving element 7%. As the control bar 60 was moved toward magnet 24 the projection 65 on the controlbar fiilpermitted the detent 25 and the projection 24a of the pawl 24 to engage the ratchet teeth 42 of the second level of the gear 4! Also,

the post 52 pivoted the bell crank 50, which in turn pivoted the element 47, removing the tip 47b of the element 47 from possible engagement with the tip 241) of the pawl 24, and removing the projection 47a of the element 47 from possible engagement with the teeth i3 of the first level of the gear 4i Themagnet 24 is then energized and deenergized the number of times necessary to restore the switch. The energizing of the magnetZG causes theoperation of its armature 22 which in turn operates the. pawl 24 to force the projectionlda of the pawl 24 to stop thegear 49in a reverse direction.

The detent 25 holds the gear .40 as magnet Zilis deenergized and the projection 2 3a restores. Further operation of the magnet Ztl causes further reverse rotation of the gear 4d in steps. Thisrotation of the gear 4 causes areverse rotation of the driving element 7%, thereby restoring the tension to the drive spring 85), and cansing a reverse rotation of the :gear 72, which in turn will operate against the rack'67 of-the wiper assembly 6% to withdraw the wiper assembly 68 from the selected group of bank contacts thereby returning the wiper assembly 68 to normal. When'the driving element 743 has'rotated' to the position wherein the wiperassembly is normal, the lock bar 73 ,isthenin alignment-with the :slot, 76 of the-driving element .70, and the :spring 74 will cause the projections 73!: to move downward into the slot 76,

and the tip 73a of the lock bar v73: will be ,freefrom .the notchesin theplate 15. The carriage andthe driving element will now be locked'for rotationas aunit. Further operation of the magnet 2t} and the resulting rotation ofgear so which in turn causes the rotation of the driving element 7%? will return the driving element 70 with the carriage 66 to normal. Full tension will against be present in the drive spring 8%). As the driving element 70 is returned to the normal position post 64 on the under side of the driving element lit engages the projection 6th: of the control bar so, thereby forcing the notch 6%!) from engagement with the lever 17. Magnet 10 is then deenergized to complete the restoration otzthe switch.

'Having described my invention what I consider new and desire to be protected by Letters Patent is specifically set forth in the claims following.

What is claimed is:

1. In a drive mechanism for operating the wipers'of a two motion selecting switch, a first member rotatively mounted in said switch, the rotation of said member in onedirection moving said wipers in two sequential directions and the rotation of said member in a reverse direction restoring said wipers, means for rotating said first member in said one direction, restoring means for rotating said member in a reverse direction, escapement means mounted in said switch and associated with said member, a first electromagnet, operation of said first electromagnet controlling said escapernent means to control the rotation of said member in said one direction, a second electromagnet, a control bar, operation of said second electromagnet operating said control bar to cause said first electromagnet to also operate said restoring means to thereby rotate said member in a reverse di rection to restore said wipers.

,2. in a drive mechanism as claimed in claim 1, said means for rotating said first member in said one direction comprising a tensioned coil spring, said spring mounted in said switch and attached to said first memher, said tension causing said member to rotate in said one direction, said rotation of said member in a reverse direction restoring, said spring to tension.

3. in a drive mechanism for operating-the wipers of a two'motion selecting switch, a first member having a slot therein, a plurality of gear teeth mounted :on said first member, asecond member carrying said switch wipers, said members rotatively and adjacently mounted in saidswitch, meanscn said 'secondmember co-operating with said slot in said first'member to lock said members together, means forrotating said first member afirst and a second selected amount, said second memberfollowing the rotation of said'first member when saidfirst member is rotated said first selected amount, means for unlocle ing said members and for locking said second -membcr against further rotational movement, means operate-int the completion of said rotation of sai'dfirst member-said first selected amount for operating said last-mentioned means, a three level gear rotatively mounted iin said switch, one level of said three level gear in mesh with the gear teetn'of. said first member, a second level having teeth on the periphery thereof, escapenient means associated .vitlrthe teeth of said second level of said three level gear, control means actuated to operate said escapement means to control the rotation of said three level gear said first and second selected amounts to thereby control the rotation of said first member said first and second selected amounts, restoration means mounted in said switch and associated with a third level of said three level gear, said control means also actuated'at a later time to operate said restoration means to rotate said gear in a reverse direction to thereby rotate said first member in a reverse direction to thereby'restore said wipers.

a drive mechanism as claimed in claim 3, said restoration means comprising an electromagnet mounted a in said switch and having an armature pivotally mounted thereon, a pawl pivotally mounted on said armature, said pawl movable to en age said third level of said three level gear, a detent pivotally mounted in said switch and movable to engage said third level of said three levc gear, means in said switch for moving said pawl and said detent to engage said third level of said three level gear, the energiz ng and deenergizing of said electromagnet causing said pawl to rotate said three level gear in steps in said reverse direction to thereby rotate said first member in said reverse direction.

5. In a drive mechanism as claimed in claim 3, said cscapement means comprising a first and second detent biased toward each other, pivotally mounted in said switch, and engageable with said second level of said three level gear, said first detent having a projection thereon engageable with said second detent, said detents so positioned that each detent in turn engages one of the teeth of said second level, a pawl operating against said first escapement detent, an electromagnet mounted in said switch having an armature pivotally mounted thereon, said armature pivotally attached to said pawl, said electromagnet energized to operate said pawl, said pawl operating to free said first detent, said second detent then engaging one of the teeth of said second level as said three level gear is rotated, said electromagnet deenergized to restore said pawl to permit said first detent to re-engage said escapement teeth, said projection on said first detent restoring said second detent to its disengaged position.

6. In a drive mechanism as claimed in claim 5, said restoration means comprising said electromagnet, annature and pawl, said pawl movable to engage the third level of said three level gear, a detent pivotally mounted in said switch and movable to engage said third level of said three level gear, means in said switch for moving said pawl out of engagement with said escapement detent and for moving said pawl and said detent to engage said third level of said three level gear to thereby rotate said three level gear in steps in said reverse direction as said electromagnet is energized and deenergized to thereby rotate said first member in said reverse direction.

7. In an electric switch, a rotatable member having gear teeth thereon, a tensioned coil spring attached to said member tending to cause rotation of said member from a normal position, a rotatable shaft, a gear rigidly mounted on said shaft and meshed with said gear teeth of said rotatable member, said rotation of said member transmitted to said gear through said meshed gear teeth, an escapement wheel rigidly mounted on said shaft corotatable with said gear wheel, escapement means associated with said escapement wheel for controlling the rotation of said escapement wheel and said co-rotating gear wheel to permit said spring to rotate said rotatable member from said normal position, electromagnet means for operating said escapement means, restoring means comprising a ratchet wheel rigidly mounted on said shaft co-rotatable with said gear wheel and said escapement wheel, a pawl and detent, said electromagnetic means also operating said pawl and detent to rotate said ratchet wheel to thereby rotate said shaft in a reverse direction, the reverse rotation of said shaft being transmitted to said rotatable member by means of said gear to thereby restore said rotatable member to said normal position and restore said spring to full tension.

8. In a drive mechanism for operating the wipers of an electric switch, a rotatable wiper operating member having gear teeth thereon, a three level gear rotatably mounted in said switch, one level of said gear comprising a series of escapement teeth mounted on the periphcry of said gear, a second level of said gear comprising a series of ratchet teeth mounted on the periphery of said gear, a third level of said gear comprising a series of gear teeth mounted on the periphery of said gear, said three level gear positioned to mesh said gear teeth thereof with the gear teeth of said rotatable member, spring means normally tending to rotate said rotatable member from a normal position, rotation of said member transmitted to said three level gear by means of said meshed gear teeth on said rotatable member and said three level gear, escapement means associated with the escapement teeth of said three level gear, means for operating said escapement means to control the rotation of said gear to thereby control the rotation of said rotatable member by said spring means, restoring means comprising an operating pawl and detent associated with the ratchet teeth of said three level gear, said means operating said pawl and detent to return said rotatable member to a normal position.

9. In a drive mechanism for operating the wipers of a two motion selecting switch, a first member rotatable from a normal position, a second member carrying said switch wipers, said members rotatively and adjacently mounted in said switch, a first locking means associated with said members for locking said members together. means for rotating said first member a first and a second amount from said normal position, said second member following the rotation of said first member when said first member is rotated said first amount, a second locking means for locking said second member against further rotational movement, said second locking means simultaneously operative to unlock said members, a single pair of electromagnets, a first of said pair of electromagnets operated at the completion of said rotation of said first member said first amount to operate said second locking means, escapement means associated with said first member to control the rotation of said first member said first and second amounts, the second of said pair of electromagnets operated to control said escapement means, restoration means associated with said first member also operated by said second of said pair of electromagnets to restore said first member to said normal position, and a control bar, said control bar movable from a normal position to shift said second of said pair of electromagnets from said operation of said escapernent means to said operation of said restoration means, said first of said pair of electromagnets operated at the completion of said rotation of said first member said second amount to unlock said second member and to move said control bar from said normal position to thereby cause said second of said pair of electromagnets to operate said restoration means, restoration of said first member to said normal position operative to return said control bar to said normal position to thereby shift said second of said pair of electromagnets from said operation of said restoration means to said operation of said escapement means preparatory to the next operation of said drive mechanism. 

